This is really two questions, first, do browsers normally cache images on the client by default or does the server have to indicate that they can be cached?
Second, given that I do not have access to IIS what can I do in an ASP application to improve client side caching of images.
i haven't used this but you may be interested in taking a look at caching images in asp.net
Here is a useful link
Are you generating the images yourself, or are they static files
A well-written browser will use the HTTP headers associated with the image to determine if the image should be cached and how long it should be cached for.
Take a look at the Cache-Control, Pragma, and Expires headers in the HTTP 1.1 specification.
This is really two questions, first, do browsers normally cache images on the client by default or does the server have to indicate that they can be cached?
Browsers cache what they are allowed to. You can globally set those Headers within IIS, but you can almost always override them from within your application. Unless some ssl accelerators or firewalls override them..
Second, given that I do not have access to IIS what can I do in an ASP application to improve client side caching of images.
just look around in System.Web.HttpContext.Current.Response.Cache